An anonymous comment asked: "Would you please describe the extent to which your university - or other German universities - require students to footnote their writings?"
German universities are, I assume, just like other universities. We are trying to teach people how to think and how to write, and how to be scientific in doing so. And thus, we are not interested in something your cousin's uncle saw on TV - we want the facts, please.
The form for footnotes varies from field to field, but in general, if it's not from you, it needs a footnote.
This is not done to torture poor students who don't have much time to get those term papers written between jobs and parties. It is so that someone else who reads what you write can verify - or disprove - what you wrote. In a way, it saves your hide.
Let's say you wrote "The world is flat." You just got yourself an "F", for stupidity. But if you write "Sticklemonger writes in [Sti99] that the world is flat", then it's not your stupidity, but Sticklemonger's, and that lets you off the hook.
If you use the argumentative structure from someone without referencing it (either inline or in a footnote) and that argumentative structure is wrong, it is again your fault unless you can point to the real author.
If you like a particular phrase or some sentence sums up what you want to say perfectly - go ahead, that's what the quotes are for - quote exactly, and give us the source. Not www.nytimes.com, I'd like both for web sites and for print literature a citation that lets me find exactly what you are quoting. That is, either an exact URL (and date) or the exact edition and page number.
Someone asked me if there wasn't a way that a conscientious student could check that his paper didn't have a "mistaken plagiarism" in it. No magic here, either. Software can't see if your footnotes are set right, and it surely can't see if you are forgetting to quote some book right. The only way - and there is no royal road here - is to take notes religiously, noting down where you read what, carefully documenting quotes and dates and facts, so that you can refer to them properly.
Research is not something you google. Research takes time, patience, and discipline. It demands that you take notes, keep your work, be honest about your sources. And when you make an exciting discovery or can formulate a solid theory, it is really, really fun. Copying and cutting corners takes all the fun out of research. In Europe and elsewhere.